AbstractFifteen sexually mature rams, five each of Barki, Awassi (I, imported from Syria) and Awassi (LB, locally born in Egypt) were used to study the biochemical and enzymatic properties of seminal plasma for 12 months. The biochemical analyses of ram seminal plasma indicated that the highest values of total protein, albumin (A), globulin (G), fructose, total lipids and cholesterol were recorded in late summer and early autumn, while A/G and AST/ALT ratios exhibited the lowest values. Lowest values of the same parameters were recorded in winter and late spring, while ratios of A/G and aspartate amino transferase (AST)/alanine amino transferase (ALT) showed the highest values in spring. AST enzyme activity showed highest activity in winter and summer and lowest activity in autumn, while ALT exhibited the highest activity in winter and the lowest activity in spring. The relationships between these parameters and semen quality are discussed.